Glossary
P
160 terms.
- P-header
A private SIP header field whose name starts with "P-". The ones in RFC 7315 were defined for use in networks specified by the 3GPP.
Like I'm five A special label on a message that only certain phone networks know how to read.
- P-tunnel
A multicast tunnel through a service provider backbone that carries multicast traffic for a Multicast VPN between provider routers.
Like I'm five A hidden pipe inside the phone company's network that carries group messages for its customers.
- P2MP LSP
A point-to-multipoint Label Switched Path, a tree-shaped MPLS path with one root and many leaves. Traffic is copied only where the tree branches.
Like I'm five A road that starts at one place and splits to reach many places, copying a message only at the forks.
- Packet capture
Recording the packets that pass over a network link, usually saving them to a file. The saved packets can be examined later to debug problems.
Like I'm five Recording the messages travelling on a network so you can look at them later.
- Packet loss
The situation where a packet sent across a network never arrives. Fractional loss is the share of packets that go missing on a path.
Like I'm five Letters that get lost in the mail and never reach the other person.
Used in RFC 2448 RFC 2680 RFC 5560 RFC 7456 RFC 7680 RFC 7982 RFC 8382 RFC 9341
- Packet loss concealment
A technique where a decoder hides the gap left by a lost audio packet, instead of playing silence or a click.
Like I'm five Filling in a missing puzzle piece with a good guess so the picture still looks right.
- Packet Sampling
Selecting a subset of the packets seen at an observation point, using sampling or filtering techniques, and reporting on only the selected ones.
Like I'm five Looking at only some of the packets instead of every single one.
Used in RFC 5474 RFC 5475 RFC 5476 RFC 5477 RFC 6727 RFC 6728
- Packetization Layer
The layer of the network stack that segments data into packets and chooses where packet boundaries fall. TCP and SCTP are examples.
Like I'm five The part of the system that cuts a big message into packages of a chosen size.
- Padding
Extra = characters added to the end of base-encoded output so its length is a whole multiple of the encoding's block size (4 characters for Base64, 8 for Base32).
Like I'm five Filler at the end that tops up the last box so it is full.
Used in RFC 44 RFC 54 RFC 64 RFC 70 RFC 102 RFC 1014 RFC 1321 RFC 1377 RFC 1423 RFC 1570 RFC 1829 RFC 1851 RFC 2040 RFC 2406 RFC 2410 RFC 2419 RFC 2420 RFC 2451 RFC 2522 RFC 2841 RFC 3174 RFC 3182 RFC 3211 RFC 3217 and 60 more
- Padding Oracle
A weakness where a decryptor reveals whether padding was valid, letting an attacker learn plaintext by trying guesses. Checking integrity before decrypting avoids it.
Like I'm five A guard who says whether your guess was close, which lets you work out the secret.
- PANA
Protocol for carrying Authentication for Network Access. It is a UDP-based protocol that carries EAP authentication between a client and an authentication agent.
Like I'm five A way for a device to show its login to a network, sent in small messages.
- PAP
The Password Authentication Protocol. A PPP authentication protocol in which the peer sends a name and password. PPP gives it the Protocol value 0xC023.
Like I'm five Saying your name and password out loud to get in.
Used in RFC 1331 RFC 1471 RFC 1472 RFC 1661 RFC 1994 RFC 2341 RFC 2363 RFC 2364 RFC 2607 RFC 2809 RFC 2989 RFC 3127 RFC 8907
- Parameter Set
A block of H.264 settings, such as picture size, that applies to many slices. Sequence and picture parameter sets are sent separately from the slice data.
Like I'm five A cheat sheet of settings that the viewer needs before it can read the video pieces.
- Parental Agent
The parent-side entity, such as a registry or registrar, that fetches a child's CDS, CDNSKEY or CSYNC records and updates the delegation based on them.
Like I'm five The person at the parent's office who reads the child's notes and updates the records.
- Partial acknowledgment
An acknowledgment that confirms some but not all of the data outstanding when fast recovery began, indicating additional packet losses.
Like I'm five A message saying the first package arrived but others are still missing.
- Partial reliability
A transport option where some messages are sent with a delivery guarantee and others may be dropped instead of retransmitted. For SCTP it is defined in the PR-SCTP extension.
Like I'm five Some messages get a promise to arrive and others are sent without one.
- Passive attack
An attack in which the attacker only reads packets off the network and does not write any. Password sniffing is an example.
Like I'm five Listening at the door without ever knocking.
- Passive mode (PASV)
An FTP mode in which the client sends PASV, the server replies with an address and port it is listening on, and the client opens the data connection to it. Without it the server connects back to the client.
Like I'm five Instead of waiting for the server to call you back, you call the server both times.
Used in RFC 614 RFC 959 RFC 1579 RFC 1639 RFC 2428 RFC 2577 RFC 4217 RFC 8321 RFC 8889 RFC 9341
- Passphrase
A secret phrase used to encrypt a private key on disk, so that the key can be used only after the user types it.
Like I'm five A lock on your pen's case that only opens when you say the magic words.
Used in RFC 1760 RFC 1938 RFC 2289 RFC 3112 RFC 3211 RFC 4252 RFC 6030 RFC 7613 RFC 7717 RFC 8110 RFC 8125 RFC 8265 RFC 8807 RFC 9580
- PASSporT
A signed token that asserts a telephone identity in STIR. The authentication service creates it and carries it in a SIP Identity header field.
Like I'm five A signed note that says who a phone call is really from.
Used in RFC 8224 RFC 8946 RFC 9027 RFC 9118 RFC 9410 RFC 9475 RFC 9795 RFC 9888 RFC 9970
- Password verifier
A value computed from a password that a server stores in place of the password itself. It lets the server check a login without holding the password.
Like I'm five A scrambled fingerprint of your password that the server keeps instead of the password.
- Password-Authenticated Key Exchange
A cryptographic protocol that allows two parties to derive a shared secret key using a password, without revealing the password or the key to eavesdroppers.
Like I'm five Two people use a password they both know to create a secret code together without anyone watching learning the password.
- Path Computation Element
A network entity that computes a path or route from a network graph while applying constraints. Clients ask it for paths using PCEP.
Like I'm five A route planner that other devices ask for directions.
Used in RFC 4655 RFC 4657 RFC 4674 RFC 4726 RFC 5088 RFC 5089 RFC 5441 RFC 5455 RFC 5468 RFC 5520 RFC 5521 RFC 5541 RFC 5553 RFC 5862 RFC 5886 RFC 6163 RFC 6457 RFC 7025 RFC 7470 RFC 7491 RFC 7897 RFC 7926 RFC 8051 RFC 8231 and 36 more
- Path Computation Element
A component that computes network paths on behalf of other nodes, using a database of the network's topology. It answers path requests from clients called PCCs.
Like I'm five A map expert you ask for the best route instead of working it out yourself.
- Path diversity
Arranging for two connections to follow paths that share no links, nodes or risk groups. A single failure then cannot take both down.
Like I'm five Taking two different roads so that one closed bridge cannot block both trips.
- Path Key
A token that stands in for a hidden path segment. Only the path computation element it names can turn it back into the real list of nodes and links.
Like I'm five A coded ticket number that only one office can decode into the real route.
- Path MTU (PMTU)
The smallest MTU of all the links between a sender and a receiver. A datagram no bigger than the Path MTU can travel the whole way without being split up.
Like I'm five If a trip goes through many doors, the biggest box you can carry the whole way is the one that fits the smallest door.
Used in RFC 1191 RFC 1752 RFC 1905 RFC 1981 RFC 2210 RFC 2215 RFC 2401 RFC 2473 RFC 2745 RFC 2923 RFC 2960 RFC 2991 RFC 3124 RFC 3209 RFC 3542 RFC 4821 RFC 4828 RFC 4993 RFC 5061 RFC 5215 RFC 5677 RFC 5858 RFC 5927 RFC 6343 and 28 more
- Path MTU Discovery
The process by which a sender finds the largest packet that fits through every link on a route. In IPv6 it relies on ICMPv6 Packet Too Big messages, and the procedure is described in RFC 8201.
Like I'm five Sending bigger and smaller boxes until you learn the biggest one that fits through every door on the way.
Used in RFC 792 RFC 1332 RFC 1435 RFC 1726 RFC 1981 RFC 2003 RFC 2004 RFC 2067 RFC 2147 RFC 2176 RFC 2225 RFC 2414 RFC 2431 RFC 2463 RFC 2467 RFC 2473 RFC 2488 RFC 2492 RFC 2675 RFC 2784 RFC 2893 RFC 2923 RFC 2991 RFC 3032 and 81 more
- Path Property
A measurable or observable characteristic of a path element, a subpath, or an entire path. Properties can describe performance (delay, loss), resources (cost, capacity), services (available protocols), or topology (disjointness, symmetry).
Like I'm five A fact about a road: how wide it is, how fast you can go, whether it costs money, or who owns it.
- Path Signal
A message sent to or from an on-path network element, which can be implicit (derived from unintended information visibility) or explicit (intentionally designed for a specific purpose).
Like I'm five A message between an app and a router on the way, either by accident (the router reads what it sees) or on purpose (the app or router intentionally sends a message).
- Path validation
A QUIC check that an endpoint can really receive packets at a new address. One side sends a PATH_CHALLENGE frame and the other must answer with a matching PATH_RESPONSE.
Like I'm five Asking "is that really you over there?" and getting the right secret word back.
Used in RFC 3280 RFC 4806 RFC 5061 RFC 5276 RFC 5937 RFC 6010 RFC 6811 RFC 7353 RFC 8205 RFC 8206 RFC 8481 RFC 9000 RFC 9853
- Path-vector protocol
A routing protocol in which each route advertisement carries the full list of autonomous systems it has passed through. The list lets a router detect loops and apply policy to the whole path rather than just a distance.
Like I'm five Each piece of news comes with the list of every place it has been, so nobody sends it in circles.
Used in RFC 1322 RFC 1621 RFC 2545 RFC 3219 RFC 4271 RFC 4273 RFC 4274 RFC 6836 RFC 6998 RFC 7132
- PAWS
Protection Against Wrapped Sequences. A TCP mechanism that uses the Timestamps option to discard old duplicate segments when sequence numbers wrap around on a fast connection.
Like I'm five A date stamp on every letter so old, late letters can be thrown away.
- Payload type
A 7-bit field in the RTP header that says which format the payload holds, such as a particular audio codec, so the receiver knows how to decode it.
Like I'm five A label on the box saying what kind of sound is inside.
Used in RFC 1889 RFC 1890 RFC 2035 RFC 2038 RFC 2198 RFC 2250 RFC 2305 RFC 2327 RFC 2431 RFC 2658 RFC 2733 RFC 2736 RFC 2793 RFC 2823 RFC 2862 RFC 3009 RFC 3016 RFC 3047 RFC 3108 RFC 3119 RFC 3190 RFC 3264 RFC 3389 RFC 3497 and 77 more
- PBKDF2
Password-Based Key Derivation Function 2, which applies a hash function many times (the iteration count) to slow down attackers trying to guess the password.
Like I'm five A method that hashes a password many times to make it hard to guess.
- PBMAC1
Password-Based Message Authentication Code 1, a scheme for using modern key derivation functions to compute message authentication codes from a password.
Like I'm five A way to use a password to seal and check a message using modern, stronger methods.
- PCEP
The Path Computation Element Communication Protocol, used between a client and a path computation element that calculates network paths. It is defined in RFC 5440.
Like I'm five A way for a network device to ask a helper computer to work out a good route.
Used in RFC 8637 RFC 8685 RFC 8697 RFC 9005 RFC 9357 RFC 9752 RFC 9756
- PDU
A protocol data unit: one message-sized chunk of a protocol, with defined fields, that is carried between two parties.
Like I'm five One complete note that two computers pass to each other.
- Peer-to-peer
A way of building a system in which the participants both use a service and provide it to each other, instead of all relying on one central server.
Like I'm five Everyone helps everyone else instead of all asking one big helper.
Used in RFC 5594 RFC 5632 RFC 5693 RFC 5694 RFC 6029 RFC 6646 RFC 6875 RFC 6940 RFC 7285 RFC 7846
- Pel
A picture element, the smallest unit of a displayed image, which in a bitmap is a single dot that can be either black or white.
Like I'm five One tiny dot in a picture.
- Pending Interest Table (PIT)
A data structure in each forwarder that records which faces incoming requests arrived on, so replies can be forwarded back along the path they came from.
Like I'm five A list the router keeps of which door each request came through, so it knows which way to send the reply.
- Penultimate Hop Popping
Removing the top label at the second-to-last router on a path, so the final router receives the packet without that label.
Like I'm five The second-to-last stop takes off the tag so the last stop gets a cleaner package.
Used in RFC 3031 RFC 3270 RFC 5129 RFC 6373 RFC 8287 RFC 8661 RFC 8665 RFC 8667 RFC 8957
- Per-Hop Behavior
The forwarding treatment a network node applies to a packet based on its DSCP, such as priority queuing, drop precedence, or rate limiting.
Like I'm five How a router decides to handle a packet based on its sticker.
- Per-hop behavior (PHB)
The externally visible forwarding treatment a differentiated-services node gives a behavior aggregate, such as best-effort or preferential queueing. It describes the result, not the algorithm used.
Like I'm five What a worker does with a parcel at each stop, like putting it in the fast pile or the slow pile.
Used in RFC 2474 RFC 2475 RFC 2597 RFC 2598 RFC 2697 RFC 2836 RFC 2859 RFC 2983 RFC 2996 RFC 2998 RFC 3086 RFC 3140 RFC 3175 RFC 3246 RFC 3247 RFC 3248 RFC 3260 RFC 3270 RFC 3287 RFC 3289 RFC 3290 RFC 3308 RFC 3644 RFC 3670 and 21 more
- Percent-encoding
A way to write any byte inside a URI as a percent sign followed by two hexadecimal digits, for example
%20for a space. It is used for bytes outside the allowed character set and for reserved characters that must be treated as plain data.Like I'm five A secret code for awkward letters: you write a percent sign and two digits instead of the letter itself.
Used in RFC 1630 RFC 1738 RFC 2017 RFC 2141 RFC 2184 RFC 2231 RFC 2254 RFC 2255 RFC 2368 RFC 2392 RFC 2396 RFC 3368 RFC 3966 RFC 3986 RFC 3987 RFC 4088 RFC 4501 RFC 4516 RFC 4622 RFC 5023 RFC 5092 RFC 5122 RFC 5137 RFC 5435 and 20 more
- Perfect forward secrecy
A property of key-establishment in which compromise of a session key or long-term private key after a session does not compromise earlier sessions. RFC 4251 notes that SSH Diffie-Hellman key exchanges provide it.
Like I'm five Even if a thief finds today's key, yesterday's locked boxes stay locked.
Used in RFC 1984 RFC 2409 RFC 2412 RFC 2786 RFC 3268 RFC 3585 RFC 3830 RFC 4101 RFC 4251 RFC 4279 RFC 4430 RFC 4492 RFC 4650 RFC 5246 RFC 5479 RFC 5487 RFC 5489 RFC 5590 RFC 5683 RFC 5763 RFC 5931 RFC 5953 RFC 6124 RFC 6189 and 51 more
- Perfect forward secrecy
A property of a key agreement protocol where compromising the long-term secret key does not compromise the security of past session keys.
Like I'm five Even if someone steals the master password later, they still cannot read old conversations.
- Performance Metric
A quantitative measure of performance for an IETF-specified protocol, or for an application carried over one. Examples include the DNS response time to resolve an address.
Like I'm five A number that tells you how well something on a network is working, like how long a page takes to load.
- Persistent connection
An HTTP/1.1 connection that stays open after a response so further requests can reuse it. It is the default in HTTP/1.1; a
Connection: closeoption ends it.Like I'm five A phone line you keep open between questions instead of hanging up each time.
Used in RFC 2068 RFC 2616 RFC 2818 RFC 3010 RFC 5923 RFC 6202 RFC 6712 RFC 7230 RFC 7766 RFC 8895 RFC 9112 RFC 9931
- Persistent identifier
A name or number that refers to the same resource for as long as the resource exists, independent of the resource's physical location or the organization maintaining it.
Like I'm five A permanent name that never changes even if the website moves.
- Pervasive Monitoring
Widespread surveillance of Internet communications at a scale that affects all users and services, as described in RFC 7258 as a threat to privacy on the Internet.
Like I'm five Mass spying on everyone's Internet activity all the time.
- PHB Scheduling Class
A Per-Hop Behavior group for which a common constraint is that ordering of at least those packets belonging to the same microflow must be preserved.
Like I'm five A group of forwarding behaviors where packets from the same conversation must stay in order.
- PIDF
The Presence Information Data Format, a basic XML format for presenting presence information about a presentity. Extensions add further elements to it.
Like I'm five The standard form that online-status messages are written on.
Used in RFC 3856 RFC 3922 RFC 4079 RFC 4479 RFC 4481 RFC 4482
- PIDF-LO
Presence Information Data Format Location Object; an XML-based standard format for conveying location information in SIP and other Internet protocols.
Like I'm five A standard way to write location information so any emergency system can understand it.
- Ping
A tool that sends an ICMP Echo Request to a host and waits for an Echo Reply, to check that it is reachable and to time the round trip.
Like I'm five Shouting "hello?" down a hallway and listening for the echo.
Used in RFC 240 RFC 252 RFC 255 RFC 267 RFC 791 RFC 792 RFC 889 RFC 1470 RFC 1574 RFC 1575 RFC 1578 RFC 1739 RFC 2151 RFC 2463 RFC 2466 RFC 2681 RFC 2925 RFC 2991 RFC 3542 RFC 3763 RFC 4377 RFC 4379 RFC 4560 RFC 5085 and 44 more
- Ping and Pong
Control frames (opcodes 0x9 and 0xA). A Ping asks if the other side is alive, and the receiver should answer with a Pong.
Like I'm five 'Are you there?' and 'Yes!'
Used in RFC 6455
- Pinhole
A narrow opening in a firewall that permits one specific TCP or UDP session, whose ports are determined dynamically, to pass through.
Like I'm five A tiny door opened just for one visitor and nobody else.
- Pipelining
Sending several requests over one connection without waiting for each reply. Responses may then return out of order and are matched to requests by an identifier.
Like I'm five Asking many questions in a row instead of waiting after each one.
Used in RFC 1203 RFC 1936 RFC 2033 RFC 2068 RFC 2326 RFC 2371 RFC 2449 RFC 2616 RFC 2920 RFC 3030 RFC 3207 RFC 3502 RFC 3656 RFC 3977 RFC 4037 RFC 4468 RFC 4644 RFC 4954 RFC 4991 RFC 4992 RFC 5182 RFC 5734 RFC 6202 RFC 6851 and 13 more
- PKCE
Proof Key for Code Exchange, defined in RFC 7636. The client sends a hashed secret with the authorization request and the original secret with the token request, so a stolen authorization code is useless to an attacker.
Like I'm five A secret handshake that proves the one who asked for the ticket is the one cashing it in.
Used in RFC 6749 RFC 7636 RFC 8252 RFC 8414 RFC 9126 RFC 9449 RFC 9700 RFC 10017 RFC 10027
- PKI
Public key infrastructure. The CAs, certificates, policies and validation rules that let parties trust public keys.
Like I'm five The whole system of ID offices and rules for checking them.
Used in RFC 1422 RFC 2312 RFC 2459 RFC 2510 RFC 2527 RFC 2528 RFC 2559 RFC 2560 RFC 2585 RFC 2587 RFC 2797 RFC 2986 RFC 3029 RFC 3161 RFC 3193 RFC 3280 RFC 3447 RFC 3647 RFC 3709 RFC 3739 RFC 3740 RFC 3820 RFC 4043 RFC 4059 and 110 more
- PKINIT
Public Key Cryptography for Initial Authentication in Kerberos. It lets a client authenticate to the KDC with a certificate and private key instead of a password.
Like I'm five Showing your ID card instead of saying a secret password.
- Platform Configuration Register
A TPM storage slot that holds a rolling hash of the measurements added to it.
Like I'm five A notebook page that can only be added to, never erased, so it always shows what happened.
- Pledge
In BRSKI, a prospective, unconfigured device that has an identity installed at the factory and is trying to join a network domain.
Like I'm five The brand-new device that wants to join a network.
- PMSI
P-Multicast Service Interface: a conceptual interface a PE uses to send customer multicast traffic to all PEs in a VPN (inclusive) or to some of them (selective).
Like I'm five The mailing list a router uses to send one message to many routers.
- pNFS
Parallel NFS, a feature of NFSv4.1 that lets clients read and write data by means other than sending those operations to the server. The server manages the metadata.
Like I'm five A librarian who tells you which shelf has your book so you can fetch it yourself.
- pNFS layout
The information a pNFS client uses to reach file data on storage devices. It names the protocol (the layout type) and the storage devices to use.
Like I'm five A map showing where the pieces of a file are kept.
- Point code
The identifier of a node that has an MTP3 layer in an SS7 network. Each M2PA IP Signaling Point must have its own point code.
Like I'm five A phone-network node's own street address.
- Point of Local Repair
The router next to a failed link or node that detects the failure and moves traffic onto a pre-computed alternate path.
Like I'm five The traffic helper standing right at the broken bridge who waves cars onto the other road.
Used in RFC 4090 RFC 4561 RFC 6414 RFC 6894 RFC 7715 RFC 7811 RFC 7812 RFC 8104 RFC 8271 RFC 8400 RFC 8537 RFC 8679 RFC 8796 RFC 9705 RFC 9855 RFC 9912
- Point of Presence
A physical location where an Internet Service Provider operates access servers that users can dial in to.
Like I'm five A building or data center where an ISP's dial-in numbers are located, typically in major cities.
- Point-to-multipoint LSP
A label switched path with one ingress and several egress routers. It is built from multiple source-to-leaf sub-LSPs overlaid to form a tree.
Like I'm five A road network shaped like a tree, from one trunk out to many branches.
- Point-to-point link
A link with exactly two ends, such as a cable between two routers. No other devices share it.
Like I'm five A string tied between two tin cans, with nobody else on the line.
- Poisson sampling
A way of choosing measurement times at random, with a fixed average rate. It avoids lining up with regular patterns in the traffic and limits bias.
Like I'm five Checking at random moments instead of on a fixed beat.
Used in RFC 2330 RFC 2679 RFC 2680 RFC 3393 RFC 3432 RFC 5814 RFC 7312 RFC 7680
- Policy Decision Point
The server that makes policy decisions. In COPS it answers the requests that a policy enforcement point sends.
Like I'm five The manager who decides yes or no when the guard asks.
Used in RFC 2748 RFC 2749 RFC 2753 RFC 2768 RFC 2904 RFC 2906 RFC 3084 RFC 3182 RFC 3198 RFC 3313 RFC 3520 RFC 3571 RFC 3644 RFC 4261 RFC 7149
- Policy Enforcement Point
A network device (router, switch, access control device) that receives policies from a PDP and applies them to network traffic.
Like I'm five A device that receives rules from the manager and follows them.
Used in RFC 2748 RFC 2749 RFC 2753 RFC 2872 RFC 3084 RFC 3198 RFC 3483 RFC 3571 RFC 3644 RFC 4261 RFC 10065
- Policy Gateway
A physical router at the boundary of an administrative domain, responsible for forwarding transit traffic according to the domain's transit policies and participating in IDPR path setup.
Like I'm five A router at the edge of a network that decides whether to let traffic in or out based on the network's rules.
- Policy Information Base (PIB)
A structured database of configuration classes and instances that define policy to be downloaded to a network device, such as a router, to control its behavior.
Like I'm five A form that you fill out and send to a router to tell it how to behave.
- Policy rule
A binding of an action to a condition that selects a set of packets. In MIDCOM each rule has exactly one action, either reserve or enable.
Like I'm five A rule that says when this kind of packet shows up, do this one thing.
- Poll Sequence
A request-and-answer exchange in which one system flags a packet as a Poll and the other answers with a Final, used to confirm a parameter change or connectivity.
Like I'm five Asking are you there and waiting for a yes.
- Polling
Repeatedly asking a system for its current data at intervals, rather than being told when something changes.
Like I'm five Asking again and again whether something is ready yet.
- Pool Element
A single server instance that has registered itself as part of a server pool.
Like I'm five One server in the pool.
- Pool Handle
A logical name or identifier that points to a server pool, used by clients to refer to the pool without needing to know individual server addresses.
Like I'm five The name of a checkout counter section, like 'Express Lane'.
- POP3
The Post Office Protocol, version 3. A simple TCP protocol (port 110) that lets a mail client download messages from a maildrop on a server.
Like I'm five The way you pick up your mail from the post office.
Used in RFC 1056 RFC 1081 RFC 1082 RFC 1176 RFC 1203 RFC 1225 RFC 1460 RFC 1725 RFC 1733 RFC 1734 RFC 1844 RFC 1939 RFC 1957 RFC 2195 RFC 2384 RFC 2444 RFC 2449 RFC 2595 RFC 2683 RFC 3206 RFC 3249 RFC 3656 RFC 4409 RFC 4416 and 11 more
- Port Control Protocol
A protocol, defined in RFC 6887, that lets a client ask a NAT or firewall to create and manage port mappings, for example through its MAP opcode.
Like I'm five A way for a computer to politely ask the network door which numbered mailboxes it may use.
- Port forwarding
Carrying ordinary TCP connections through an SSH connection. Local forwarding opens a direct-tcpip channel, and remote forwarding is requested with tcpip-forward and delivered through forwarded-tcpip channels.
Like I'm five A secret tunnel: what you put in one end comes out of a door at the other end.
Used in RFC 4254 RFC 6269 RFC 6346 RFC 6431 RFC 6886 RFC 6887 RFC 6970 RFC 7393 RFC 7843 RFC 8045 RFC 8455 RFC 9987
- Port number
A 16-bit number in the TCP header that identifies an application service on a host, so many conversations can share the same pair of addresses.
Like I'm five Like an apartment number: the street address gets the mail to the building, and the number tells which door.
Used in RFC 61 RFC 62 RFC 65 RFC 175 RFC 349 RFC 429 RFC 470 RFC 503 RFC 617 RFC 675 RFC 717 RFC 731 RFC 750 RFC 755 RFC 758 RFC 761 RFC 762 RFC 768 RFC 770 RFC 776 RFC 790 RFC 793 RFC 807 RFC 811 and 290 more
- Port Set ID (PSID)
An identifier for a range of transport-layer ports assigned to one client. Together with a shared IPv4 address it identifies that client's lease.
Like I'm five A label saying which group of door numbers belongs to you.
- Port Set Identifier (PSID)
A value that identifies the set of transport ports assigned to one customer when several customers share a single IPv4 address. A PSID of k bits gives a sharing ratio of 2^k.
Like I'm five Your own range of door numbers at an address that many families share.
- Post-quantum cryptography
Cryptographic algorithms designed to stay secure even against attackers who have large quantum computers.
Like I'm five Secret codes built to still work when computers become much more powerful.
Used in RFC 8778 RFC 9370 RFC 9794 RFC 9814 RFC 9851 RFC 9881 RFC 9882 RFC 9909 RFC 9954 RFC 9964 RFC 9980
An extra secret shared in advance by two IKEv2 peers and mixed into key derivation. It keeps the derived keys safe even if a quantum computer breaks the Diffie-Hellman exchange.
Like I'm five A secret both friends already know, mixed in so future super-computers cannot crack the lock.
- Posture assessment
The process of collecting the configuration and status of an endpoint's hardware and software and evaluating it against a security compliance policy.
Like I'm five A health check for a computer before it is allowed to join the network.
- Potential Router List
A set of IPv4 addresses of routers that a tunneling host may use for router and prefix discovery. Each entry has its own refresh timer.
Like I'm five A short list of routers a computer is allowed to ask for directions.
- PPP
The Point-to-Point Protocol. A standard way to carry network-layer packets over a link between exactly two peers, with its own control protocols for setting up the link and each network protocol.
Like I'm five A polite handshake and set of rules for two computers joined by a single wire.
Used in RFC 1144 RFC 1172 RFC 1220 RFC 1331 RFC 1332 RFC 1334 RFC 1376 RFC 1377 RFC 1378 RFC 1471 RFC 1472 RFC 1473 RFC 1474 RFC 1547 RFC 1548 RFC 1549 RFC 1552 RFC 1553 RFC 1570 RFC 1598 RFC 1618 RFC 1619 RFC 1634 RFC 1638 and 140 more
- PPPoE
PPP over Ethernet, a method of carrying PPP sessions inside Ethernet frames. It adds a discovery stage to find the peer and set up a session identifier.
Like I'm five A way to do dial-up style logins over an Ethernet cable.
- Pre-authentication
Proof of knowledge of the client's key sent with the initial request, such as an encrypted timestamp. It stops the KDC handing out password-protected ciphertext to anyone who asks.
Like I'm five Showing you know the secret before the helper gives you anything.
Used in RFC 2060 RFC 4120 RFC 4556 RFC 4557 RFC 5247 RFC 5836 RFC 5873 RFC 6113 RFC 6252 RFC 6560 RFC 6697 RFC 6806 RFC 7268 RFC 8070 RFC 8129 RFC 8437 RFC 8636 RFC 9588
- Pre-Congestion Notification
A mechanism where routers mark packets before actual congestion occurs, signaling to edge routers that traffic is approaching capacity limits.
Like I'm five The lifeguard says "it is getting crowded" before people are bumping into each other.
Used in RFC 5559 RFC 5670 RFC 6660 RFC 6661 RFC 6662 RFC 7417
A secret that both sides already hold before a handshake, either configured ahead of time or derived from an earlier connection. TLS 1.3 uses PSKs for resumption.
Like I'm five A secret password you and a friend agreed on earlier.
Used in RFC 1244 RFC 2412 RFC 3562 RFC 3723 RFC 3788 RFC 3821 RFC 3830 RFC 4107 RFC 4109 RFC 4186 RFC 4279 RFC 4449 RFC 4563 RFC 4650 RFC 4738 RFC 4754 RFC 4764 RFC 4785 RFC 4851 RFC 4868 RFC 4895 RFC 5018 RFC 5054 RFC 5355 and 69 more
- Precertificate
A preannouncement of a certificate that a CA submits to a log before issuing it. Signing one indicates the CA's binding intent to issue the matching certificate.
Like I'm five A draft of an ID card that is shown to the public book before the real card is made.
- PRECIS
A framework from the IETF for the preparation, enforcement and comparison of internationalized strings in application protocols. It replaces stringprep for this purpose.
Like I'm five A set of spelling rules that makes sure names written with letters from any language are compared fairly.
- Precision Time Protocol
A time synchronization protocol specified in IEEE Std 1588-2008, which can provide synchronization as fine as nanoseconds. Clocks in a network use it to agree on the time.
Like I'm five A way for clocks in a network to agree on the exact time, down to tiny fractions of a second.
- Preemption
Taking resources away from an existing lower-priority reservation so that a higher-priority request can be admitted.
Like I'm five Someone more important takes your spot in line.
Used in RFC 2787 RFC 4128 RFC 4412 RFC 4495 RFC 4829 RFC 5975 RFC 7412
- Preemption Priority
A rank that says how important a flow is compared with others competing to be admitted. A node that is full can use it to drop less important admitted flows and make room for a more important new one.
Like I'm five A rank that lets an important newcomer take the place of a less important one when things are full.
- Prefix
The leading bits of an address that identify a network, together with how many bits there are. In 192.168.99.0/24 the prefix is the first 24 bits.
Like I'm five The front part of an address that says which neighborhood you are in.
Used in RFC 1629 RFC 1771 RFC 1786 RFC 1887 RFC 1888 RFC 1930 RFC 2072 RFC 2260 RFC 2280 RFC 2332 RFC 2342 RFC 2373 RFC 2439 RFC 2462 RFC 2546 RFC 2622 RFC 2725 RFC 2772 RFC 2827 RFC 2858 RFC 2894 RFC 2909 RFC 2966 RFC 3056 and 170 more
- Prefix code
A set of bit patterns in which no pattern is the beginning of another, so a decoder can read a stream symbol by symbol without ambiguity. It is usually drawn as a binary tree with symbols on the leaves.
Like I'm five A code where you always know where one letter ends and the next starts.
- Prefix delegation
A DHCPv6 mechanism by which a service provider hands a router a block of IPv6 addresses to divide among its own networks.
Like I'm five The internet company gives your router a whole street of addresses to hand out to rooms in your house.
Used in RFC 3769 RFC 3904 RFC 4241 RFC 5571 RFC 6204 RFC 6276 RFC 6603 RFC 6653 RFC 6853 RFC 7084 RFC 7368 RFC 7788 RFC 7849 RFC 7955 RFC 8168 RFC 8415 RFC 8992 RFC 9096 RFC 9243 RFC 9762 RFC 9818 RFC 9915
- Prefix Information Option
Part of an IPv6 Router Advertisement message that specifies a network prefix and its associated lifetime values, used by hosts to autoconfigure addresses.
Like I'm five The part of a router's announcement that tells computers which network addresses to use.
- Premaster secret
The shared secret that the key exchange produces in a TLS handshake. TLS then uses it to compute the master secret, from which the session keys are derived.
Like I'm five The first shared secret, which gets mixed into the real session keys.
- Presence
Information about whether an entity is currently available for communication. In XMPP it is carried by the presence stanza and sent to everyone subscribed to it.
Like I'm five The green dot that shows a friend is online.
Used in RFC 2778 RFC 2779 RFC 3343 RFC 3428 RFC 3680 RFC 3693 RFC 3856 RFC 3857 RFC 3858 RFC 3859 RFC 3860 RFC 3861 RFC 3862 RFC 3863 RFC 3903 RFC 3920 RFC 3922 RFC 3923 RFC 3953 RFC 3994 RFC 4079 RFC 4119 RFC 4235 RFC 4245 and 59 more
- Presence agent
The server-side entity that stores a user's presence information and sends it to authorized subscribers in notifications.
Like I'm five The helper that knows whether your friend is available and tells you when it changes.
- Presence subscription
An approval by a user that lets another entity see whether the user is available. It persists across sessions until the contact unsubscribes or the user cancels it.
Like I'm five Permission you give a friend to see your online light.
- Presentation Context
A pairing of an abstract syntax (what the data means) and a transfer syntax (how it is encoded on the wire). Multiple presentation contexts can be negotiated during connection setup.
Like I'm five An agreement between two computers about what kind of data they are sending and how it will be packaged.
- Presentity
The entity whose presence information is published and shared, such as a user. A presence user agent publishes on its behalf.
Like I'm five The person whose status board everyone else reads.
Used in RFC 3856 RFC 3863 RFC 4479 RFC 4480 RFC 4481 RFC 4482 RFC 5196 RFC 5264 RFC 5344 RFC 5962
- Principal
A uniquely named client or service in Kerberos, identified by a realm and one or more name components, such as a user or a host service.
Like I'm five A name tag for a person or a service.
Used in RFC 1510 RFC 1964 RFC 2078 RFC 2261 RFC 2623 RFC 2712 RFC 2743 RFC 2744 RFC 2853 RFC 3007 RFC 3411 RFC 3744 RFC 4120 RFC 4430 RFC 4791 RFC 5178 RFC 5179 RFC 5397 RFC 5588 RFC 5590 RFC 5591 RFC 5592 RFC 6065 RFC 6111 and 15 more
- Private address
An IP address from a block reserved for use inside organizations and not routed on the public Internet. RFC 1918 reserves 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.
Like I'm five A house number that only makes sense inside your own neighbourhood.
Used in RFC 1335 RFC 1597 RFC 1627 RFC 1631 RFC 1687 RFC 1814 RFC 1918 RFC 2050 RFC 2101 RFC 2267 RFC 2663 RFC 2685 RFC 2735 RFC 2764 RFC 2767 RFC 2775 RFC 2993 RFC 3022 RFC 3024 RFC 3027 RFC 3056 RFC 3102 RFC 3103 RFC 3235 and 49 more
- Private Enterprise Number
A number that IANA assigns to an organization so that it can be identified in protocol identifiers. Assignments can be requested from IANA.
Like I'm five A company ID number given out by a central office, like a school ID.
- Private-key Generator
A trusted server in an identity-based encryption system that holds a master secret. After authenticating a user, it calculates and returns that user's private key.
Like I'm five The key office that checks your ID and then hands you your personal key.
- Proactive routing
A routing approach in which routers regularly exchange topology information so that routes to all destinations are already known when needed. This avoids waiting for a route discovery before sending data.
Like I'm five Keeping an up-to-date map ready instead of asking for directions when you set off.
- Probing
In mDNS, the step before claiming a name in which a host sends three queries 250 ms apart asking whether anyone else already uses it. If none answers, it announces the name; if one does, it picks a different name.
Like I'm five Asking three times whether anyone already has a name before you take it.
Used in RFC 6762
- Production rule
A named definition in a grammar. In ABNF it has the form
name = elements, and the name can then be used inside other rules.Like I'm five A recipe card with a name, saying what that name is made of.
Used in RFC 5234
- Promiscuous mode
A setting in which a network interface accepts all frames it can see on the medium, not only those addressed to it. Monitoring tools use it to silently watch traffic.
Like I'm five Like a person at a party who listens to every conversation in the room, not just the ones where someone says their name.
- Proof of possession
A demonstration, such as signing a value or decrypting one, that a requester controls the private key matching the public key it wants certified.
Like I'm five Showing you really own the key to a lock before getting a card for it.
Used in RFC 2510 RFC 2797 RFC 2875 RFC 4210 RFC 4211 RFC 5272 RFC 6717 RFC 6955 RFC 7030 RFC 7800 RFC 8705 RFC 8747 RFC 9148 RFC 9200 RFC 9202 RFC 9203 RFC 9431 RFC 9483 RFC 9594 RFC 9810 RFC 9883 RFC 10002 RFC 10004
- Proposed Standard
The entry-level standards-track maturity level: stable and reviewed, but not yet proven by interoperable implementations.
Like I'm five A first official version that is promising but still being tried out.
Used in RFC 1100 RFC 1140 RFC 1160 RFC 1264 RFC 1410 RFC 1500 RFC 1540 RFC 1600 RFC 1602 RFC 1610 RFC 1780 RFC 1796 RFC 1880 RFC 2000 RFC 2005 RFC 2017 RFC 2026 RFC 2158 RFC 2160 RFC 2200 RFC 2221 RFC 2232 RFC 2241 RFC 2244 and 91 more
- Protected Access Credential
A credential handed to a peer for faster later authentication. It holds a shared secret, an opaque element the server can read, and optional extra information.
Like I'm five A special pass the guard gives you so you can get in quicker next time.
- Protection Switching
The automatic transfer of traffic from a primary path to a backup path in response to a failure, degradation, or operator command.
Like I'm five Instantly rerouting traffic from a broken path to a working backup path.
Used in RFC 3386 RFC 3469 RFC 6372 RFC 6378 RFC 7271 RFC 7347 RFC 8234
- Protocol
A formal set of rules and procedures that govern how data is transmitted and received between systems on a network, such as TCP for reliable communication or IP for packet delivery.
Like I'm five A set of rules that both computers agree to follow so they can understand each other's messages.
- Protocol Data Unit
The unit of message a protocol sends, made up of a header and usually some data. iSCSI uses the term for each message exchanged between initiator and target.
Like I'm five One labelled envelope that a protocol sends.
- Protocol Extension
A feature or capability added to a protocol to provide new functionality while maintaining compatibility with the original protocol specification.
Like I'm five A new feature you can add to a protocol to make it do new things without breaking how it worked before.
- Protocol Independent Multicast
A family of multicast routing protocols with Sparse Mode, Dense Mode and Bidirectional variants.
Like I'm five A set of rules routers use to send one message to many receivers without wasting copies.
Used in RFC 2934 RFC 5186 RFC 5496 RFC 6395 RFC 6826 RFC 7431 RFC 8059 RFC 9128
- Protocol Independent Multicast - Sparse Mode
A multicast routing protocol designed for networks where senders and receivers are sparsely distributed. PIM-SM uses a Rendezvous Point to discover sources and builds multicast distribution trees on demand.
Like I'm five A way to broadcast one stream to many listeners when senders and listeners are spread out across a network.
- Protocol Independent Multicast (PIM)
A family of multicast routing protocols whose version 2 messages share a common header with a version, a type, flag bits and a checksum.
Like I'm five The set of rules routers use to send one message to a whole group of receivers.
- Protocol Parameter Registry
A centrally maintained database that records assigned values for a protocol parameter and documents what each value means, ensuring consistent interpretation across all implementations.
Like I'm five A shared list of numbers and their meanings, kept in one place so everyone uses them the same way.
- Protocol Status
The implementation expectation for a protocol: required (all systems must implement), recommended (systems should implement), elective (optional), or not recommended (discouraged).
Like I'm five Whether everyone needs it, everyone should have it, or it is optional.
- Prover and verifier
The two roles in RFC 6238. The prover (a hardware token or an authenticator app) generates the one-time password. The verifier (the authentication or validation server) recomputes it and checks that it matches.
Like I'm five One side shows the code to prove who it is, and the other side checks it.
Used in RFC 2944 RFC 6238 RFC 9334 RFC 9683 RFC 9684 RFC 9783
- Provider Edge
A device at the edge of a service provider's network that connects customer networks to the provider's core.
Like I'm five The door where a customer's network meets the carrier's network.
Used in RFC 3769 RFC 3916 RFC 4026 RFC 4029 RFC 4031 RFC 4664 RFC 4665 RFC 4762 RFC 5085 RFC 5251 RFC 6215 RFC 6310 RFC 6658 RFC 6870 RFC 7023 RFC 7209 RFC 7309 RFC 7727 RFC 7734 RFC 9026 RFC 9161 RFC 9182 RFC 9252
- Provider Edge router
A router at the edge of a service provider's network that attaches to customer sites and holds the per-customer VPN routing tables. It is often shortened to PE.
Like I'm five The provider's front-door router that connects to each customer.
Used in RFC 2547 RFC 4176 RFC 4381 RFC 4577 RFC 6513 RFC 7582
- Provider-defined identifier (PID)
A name chosen by an ALTO server for a group of IPv4 and IPv6 addresses in a network map. The same PID name can mean different address sets in different network maps.
Like I'm five A team name for a group of addresses.
- Provider-Independent (PI) address
Address space assigned to an end site that does not come from an ISP's allocation. It lets the site change providers without renumbering, but it cannot be aggregated into a provider's prefix.
Like I'm five A mailbox number that stays with you when you switch mail carriers.
- Provisioning Class (PRC)
A type of policy data that defines a configuration object, with attributes and rules for how instances of that class should be interpreted by a device.
Like I'm five A template or form type that describes what information goes in a policy configuration.
- Provisioning Domain (PvD)
A consistent set of network configuration information (DNS servers, gateways, source prefixes) that belongs together and is used for making routing and connectivity decisions.
Like I'm five A labeled bundle of network settings that work together.
- Proxy
A server that sits between a client and an origin server and forwards requests on the client's behalf. In HTTP a proxy can demand its own authentication with status 407.
Like I'm five A middleman who passes your messages along.
Used in RFC 1919 RFC 1928 RFC 1929 RFC 1941 RFC 1961 RFC 2186 RFC 2187 RFC 2193 RFC 2196 RFC 2221 RFC 2227 RFC 2273 RFC 2295 RFC 2571 RFC 2573 RFC 2576 RFC 2577 RFC 2594 RFC 2607 RFC 2617 RFC 2647 RFC 2663 RFC 2703 RFC 2756 and 139 more
- Proxy Mobile IPv6
A mobility scheme in which the network, rather than the device, handles movement. A Mobile Access Gateway signals to a Local Mobility Anchor on the device's behalf.
Like I'm five Your phone keeps its address while moving, and the network does the paperwork for it.
Used in RFC 5845 RFC 6463 RFC 6572 RFC 6757 RFC 7156 RFC 7561 RFC 7847 RFC 8278
- Pseudo wire
An emulated point-to-point connection over a packet switched network that allows two nodes to be interconnected with any L2 technology. It joins two provider edge devices.
Like I'm five A pretend cable made out of a shared network.
- Pseudo-header
A set of IPv6 header fields, including the source and destination addresses and the Next Header value, that is included when computing the ICMPv6 checksum but is not sent as part of the ICMPv6 message itself.
Like I'm five Some details from the outside of the envelope that you also count when checking the letter.
Used in RFC 64 RFC 768 RFC 1010 RFC 1180 RFC 1347 RFC 2385 RFC 2463 RFC 2675 RFC 2682 RFC 3242 RFC 3545 RFC 3715 RFC 3828 RFC 4443 RFC 4504 RFC 4981 RFC 5925 RFC 6145 RFC 6235 RFC 6296 RFC 6935 RFC 6936 RFC 7276 RFC 7498 and 8 more
- Pseudo-header field
A special HTTP/2 field whose name starts with a colon, such as
:methodor:status. It carries the information that HTTP/1.1 puts in the request line or status line.Like I'm five A labeled box on the form for the most basic facts, like where to go and what to fetch.
- Pseudo-nickname
A single nickname that stands for a whole edge group of RBridges, so remote RBridges see one source for the group instead of several.
Like I'm five One shared name tag worn by a team so outsiders see it as one player.
- Pseudo-random number generator
An algorithm that turns a short seed into a long sequence of numbers that look random. Ordinary ones are fully predictable once the state is known, so security uses need cryptographically strong generators started from a seed with enough entropy.
Like I'm five A machine that makes a very long list of random-looking numbers from one secret starting number.
Used in RFC 1750 RFC 2437 RFC 2680 RFC 2777 RFC 2943 RFC 4056 RFC 4086 RFC 4122 RFC 4432 RFC 4537 RFC 4814 RFC 5083 RFC 5475 RFC 5832 RFC 6056 RFC 6436 RFC 6979 RFC 7091 RFC 8419 RFC 8682 RFC 8778 RFC 8954 RFC 9416 RFC 9814
- Pseudo-terminal
A software imitation of a text terminal that lets a remote program behave as though a person were typing at a real screen and keyboard. An SSH client asks for one with the pty-req request.
Like I'm five A pretend screen and keyboard so a program thinks someone is sitting right there.
- Pseudonode
A virtual node that represents a shared LAN in link state routing, so that each router reports one adjacency to it instead of one to every neighbor.
Like I'm five A pretend meeting spot that stands in for the whole street, so everyone only needs to say they are at the meeting spot.
- Pseudonym
An identifier used in place of a real identity. It is a unique bit string that can be used for authentication without revealing who the holder is.
Like I'm five A nickname you use so people do not learn your real name.
- Pseudorandom function (PRF)
A keyed function whose output looks random. IKE uses a negotiated PRF to turn nonces and a shared secret into SKEYSEED and then into all other keys.
Like I'm five A blender that turns a few secret ingredients into lots of unpredictable keys.
Used in RFC 2246 RFC 2412 RFC 2857 RFC 2898 RFC 3830 RFC 3961 RFC 4109 RFC 4306 RFC 4346 RFC 4357 RFC 4383 RFC 4401 RFC 4402 RFC 4418 RFC 4434 RFC 4615 RFC 5191 RFC 5288 RFC 5289 RFC 5295 RFC 5448 RFC 5705 RFC 5723 RFC 5869 and 16 more
- Pseudowire
An emulated connection carried across a packet network, here over MPLS. It is one kind of transport path that can be locked.
Like I'm five A pretend wire made out of packets that acts like a real cable.
Used in RFC 3931 RFC 4349 RFC 4385 RFC 4446 RFC 4447 RFC 4448 RFC 4553 RFC 4591 RFC 4618 RFC 4619 RFC 4623 RFC 4664 RFC 4667 RFC 4717 RFC 4719 RFC 4720 RFC 4761 RFC 4762 RFC 4842 RFC 4863 RFC 4901 RFC 5003 RFC 5085 RFC 5086 and 71 more
- PSTN
The Public Switched Telephone Network, the circuit-switched telephone system. Gateways connect it to packet networks such as the Internet.
Like I'm five The regular phone network that existed before calls went over the Internet.
Used in RFC 2848 RFC 3372 RFC 3398 RFC 3666 RFC 3976 RFC 4733 RFC 7195 RFC 8816
- PTR record
A DNS resource record that maps an IP address (in reverse format) to a hostname. PTR records enable reverse DNS lookups.
Like I'm five A record that says what name goes with an IP address, in reverse of the normal direction.
- Public key cryptography
A way of using a pair of keys: a private key kept secret and a public key shared freely. A signature made with the private key can be checked by anyone with the public key.
Like I'm five A pen only you own, whose handwriting anyone can recognise but nobody can copy.
Used in RFC 989 RFC 1040 RFC 1113 RFC 1114 RFC 1170 RFC 1186 RFC 1321 RFC 1412 RFC 1421 RFC 1422 RFC 1423 RFC 1424 RFC 1507 RFC 1508 RFC 1636 RFC 1704 RFC 1750 RFC 1751 RFC 1824 RFC 1825 RFC 1828 RFC 1848 RFC 1852 RFC 1949 and 333 more
- Public Safety Answering Point
The emergency call center that receives 911 or emergency calls and dispatches responders.
Like I'm five The 911 call center that answers emergency calls and sends help.
Used in RFC 5012 RFC 5069 RFC 5222 RFC 5582 RFC 6443 RFC 6444 RFC 6451 RFC 6739 RFC 6881 RFC 7135 RFC 7378 RFC 7840 RFC 8147 RFC 8148 RFC 8876 RFC 9027
- Public Safety Answering Point
The call center that answers emergency calls and dispatches or forwards them to the right responders. It is abbreviated PSAP.
Like I'm five The place where the person who answers 911-style calls sits.
- Public suffix
A domain controlled by a public registry, such as com, co.uk or pvt.k12.wy.us, under which anyone can register names. Browsers use a list of them to refuse cookies that claim to cover a whole suffix.
>Like I'm five The end part of a web address that many unrelated sites share, like .com.
- Publication point
A repository directory containing all signed objects (certificates, CRLs, ROAs, manifests) published by a RPKI certification authority.
Like I'm five A folder on a server where a CA publishes all its signed files.
- Publish/subscribe
A messaging pattern where receivers sign up for the data they want and a publisher pushes updates to them, instead of receivers asking repeatedly.
Like I'm five You sign up once and get a message whenever there is news.
- Punycode
A way of writing any Unicode string using only ASCII letters, digits and hyphens, defined as Bootstring with fixed parameters. It is used to store internationalized domain labels in the DNS.
Like I'm five A way to write fancy letters using only plain ones, so old systems can carry them.
Used in RFC 3490 RFC 3491 RFC 3492 RFC 3722 RFC 3743 RFC 3982 RFC 3987 RFC 4185 RFC 4290 RFC 4690 RFC 4952 RFC 5137 RFC 5483 RFC 5890 RFC 5891 RFC 5892 RFC 5893 RFC 5894 RFC 6055 RFC 6068 RFC 6365 RFC 6672 RFC 6763 RFC 6885 and 10 more